Welcome Back Minions!!!

Warm up on the board…

Review Question

• What defines a machine?

– 1) A device that allows you to do work in a way that is easier.

– 2) Something with a motor.– 3) Anything you hold.– 4) All the above.

Review Question

• What is an “input force”?

– 1) Something that fits inside a machine.– 2) Something that stores energy.– 3) The force exerted on a machine.– 4) All of the above.

Review Question

• What is an “output force”?

– 1) Force that fits on the outside of a machine.– 2) Force a machine exerts on an object.– 3) How far a machine is thrown.– 4) None of the above.

Review Question

• In what way can a machine make work easier?

– 1) Change force– 2) Change distance– 3) Change direction– 4) All of the above

Review Question

• How can you tell if a machine is efficient?

– 1) It says so on the label. – 2) The closer to 0% the better the efficiency.– 3) You feel resistance when using the machine.– 4) The closer to 100% efficiency the more efficient

the machine is.

Simple Machines…

• 6 types of “Simple Machines”– Inclined Plane– Wedge– Levers (3 classes)– Screw– Wheel & Axle– Pulley (3 classes)

Effort & Load

• Effort– Force applied to an object.

• Load– The opposition to applied force, such as a

weight to be carried or moved.

Inclined Plane

• Where do you think you have seen an inclined plane before?

Inclined Plane

• What is an inclined Plane?– Flat, sloped surface.

• Input force– Push/pull item

• Output force– Lifting object

Inclined Plane

• Mechanical Advantage

Ideal Mechanical Advantage = Length of Incline ÷ Height of Incline

• The longer the ramp, the less force needed!

Wedge

• Where do you think you have seen a wedge before?

Wedge

• What is a wedge?– A device that is thick

on one edge and tapers to a thin edge at the other end.• It is actually one incline

planes or even two incline planes back-to-back.

Wedge

• Mechanical Advantage

• The longer and thinner the wedge is, the less force needed!

Review

• What is the definition of an “effort”?

– 1) Force applied on an object.– 2) Force applied on the user.– 3) The opposition to a force.– 4) None of the above.

Review

• What is the definition of the “load”?

– 1) Force applied on an object.– 2) Force applied on the user.– 3) The opposition to a force.– 4) None of the above.

Review

• What is an inclined plane?

– 1) A wheel and axle used to lift or lower.– 2) A flat, sloped surface.– 3) A means to pull objects apart– 4) None of the above

Review

• What gives an inclined plane a better mechanical advantage?– 1) The shorter the incline the less force needed.– 2) The longer the incline the more force needed.– 3) Both 1 and 2.– 4) The longer the incline, the less force needed.

Review

• What is a wedge?

– 1) Flat, sloped surface.– 2) Two back-to-back inclined planes.– 3) A device that is thick on one edge and tapers to

a thin edge at the other end.– 4) All of the above.

HOMEWORK!!!

• Typed, not handwritten.• List 5 incline planes and 5 wedges around the

house.– Tell me what makes it an inclined plane or a

wedge.• Due tomorrow. (Tuesday, March, 12th, 2013)